iio:temperature:mlx90632: Add kerneldoc to the internal struct

Document internal/private struct for mlx90632 device.
Signed-off-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200818213737.140613-3-cmo@melexis.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/temperature/mlx90632.c

@@ -89,9 +89,16 @@
 #define MLX90632_MAX_MEAS_NUM	31 /**< Maximum measurements in list */
 #define MLX90632_SLEEP_DELAY_MS 3000 /**< Autosleep delay */
 
+/**
+ * struct mlx90632_data - private data for the MLX90632 device
+ * @client: I2C client of the device
+ * @lock: Internal mutex for multiple reads for single measurement
+ * @regmap: Regmap of the device
+ * @emissivity: Object emissivity from 0 to 1000 where 1000 = 1.
+ */
 struct mlx90632_data {
 	struct i2c_client *client;
-	struct mutex lock; /* Multiple reads for single measurement */
+	struct mutex lock;
 	struct regmap *regmap;
 	u16 emissivity;
 };